High Extinction Research Articles

Quinoidal Semiconductor Nanoparticles for NIR-II Photoacoustic Imaging and Photoimmunotherapy of Cancer.

Photoagents with ultra-high near-infrared II (NIR-II) light energy conversion efficiency hold great promise in tumor phototherapy due to their ability to penetrate deeper tissues and minimize damage to surrounding healthy cells. However, the development of NIR-II photoagents remain challenging. In this study, an all-fused-ring quinoidal acceptor-donor-acceptor (A-D-A) molecule, SKCN, with a BTP core is synthesized, and nanoparticles named FA-SNPs are prepared. The unique quinoidal structure enhances π-electron delocalization and bond length uniformity, significantly reducing the bandgap of SKCN, resulting in strong NIR-II absorption, a high molar extinction coefficient, and a photothermal conversion efficiency of 75.14%. Enhanced molecular rigidity also facilitates efficient energy transfer to oxygen, boosting reactive oxygen species generation. By incorporating the immunomodulator R848, FA-SRNPs nanoparticles are further developed, effectively modulating the tumor immune microenvironment by reducing Tregs and M-MDSCs infiltration, promoting dendritic cell maturation, M1 macrophage polarization, and activating CD8+ T cells and NK cells. Comprehensive studies using orthotopic ovarian cancer models demonstrated strong tumor targeting, photoacoustic imaging capabilities, and significant tumor suppression and metastasis inhibition, and also showing excellent therapeutic efficacy in an orthotopic breast cancer model. This study provides strong evidence for the potential application of quinoidal A-D-A molecules in cancer photoimmunotherapy.

High extinction risk of the endemic tree flora in a hyper‐diverse region of the Amazon

Societal Impact StatementThe rapid global loss of biodiversity, especially in the Neotropics, underscores the need to understand how deforestation impacts endemic plant species' extinction risk and conservation status. Due to limited ranges and habitat specialization, endemics are particularly vulnerable. Our study reveals that around 14% and 47% of Ecuadorian Amazon endemic trees are Critically Endangered and Endangered, respectively, with 41% facing high extinction risk. Traits like life‐form, fruit size, and height relate to extinction vulnerability. These findings highlight the factors driving Amazonian tree flora endangerment, providing crucial insights for conservation efforts of this fundamental component of Amazon hyper‐diverse forests.Summary Comprehensive analyses of the global conservation statuses of endemic tree species are scarce, especially for species‐rich forests. Endemic trees arguably suffer a higher extinction risk than other plant species due to their restricted geographic range and habitat specialization. Here, we present an updated assessment of the conservation status and extinction risk estimates for the endemic tree flora of the Ecuadorian Amazon, a darkspot of biodiversity. We combined an extensively verified taxonomic database of Amazon tree species abundance and occurrence with the most updated data of deforestation for this region. We found that approximately one sixth of the Ecuadorian Amazon endemic tree flora is Critically Endangered. A few clades, including Myrtaceae, Elaeocarpaceae, Fabaceae s.l., and Lauraceae, harbor one third of the Critically Endangered endemic tree species. According to our analysis, the extinction risk for endemic trees is associated not only with extrinsic factors such as deforestation but also with their ecology. Life‐form, fruit size, and maximum height are significantly related to extinction risk. Thus, endemic understory and canopy trees with small fruits are more prone to suffer extinction than emergent tree species. We argue that assessment programs should also include biological trait information in addition to geographic ranges and habitat specialization for the establishment of effective conservation strategies of this hyper‐diverse region of the Amazon.

Polarization-insensitive thermo-optic Mach-Zehnder switches on silicon.

Polarization-insensitive photonic switches are crucial for the case with random polarization states encountered in optical systems. In this paper, we propose and demonstrate a polarization-insensitive 2 × 2 thermo-optic Mach-Zehnder switch (PIMZS) on a 340-nm silicon-on-insulator (SOI) platform by incorporating low-loss polarization-insensitive multimode interference (PIMMI) couplers whose core width is varied optimally. The fabricated 2 × 2 PIMZS exhibits a low excess loss of 0.15-0.79 dB and a high extinction ratio of >24 dB for both polarizations, and low polarization-dependent loss (PDL) of <0.47 dB is achieved across the C-band.

Breaking the angular dispersion limit in thin film optics by ultra-strong light-matter coupling

Thin film interference is integral to modern photonics, e.g., allowing for precise design of high performance optical filters, photovoltaics and light-emitting devices. However, interference inevitably leads to a generally undesired change of spectral characteristics with angle. Here, we introduce a strategy to overcome this fundamental limit in optics by utilizing and tuning the exciton-polariton modes arising in ultra-strongly coupled microcavities. We demonstrate optical filters with narrow pass bands that shift by less than their half width (< 15 nm) even at extreme angles. By expanding this strategy to strong coupling with the photonic sidebands of dielectric multilayer stacks, we also obtain filters with high extinction ratios and up to 98% peak transmission. Finally, we apply this approach in flexible filters, organic photodiodes, and polarization-sensitive filtering. These results illustrate how strong coupling provides additional degrees of freedom in thin film optics that will enable exciting new applications in micro-optics, sensing, and biophotonics.

Review of Synthesis and Functionalization of Gold Nanobipyramids

Nanoparticles, as one of the nanotechnology implementations, have a potential application due to their advantages compared to bulk size. The type of nanoparticle widely used for many applications such as sensing, imaging, photothermal therapy and optical devices is a metal nanoparticle through their properties. The advantages of metal nanoparticles are unique plasmonic properties, size and shape control flexibility, low toxicity and the ability to be functionalized with other substances. Besides silver and platinum, gold become the most popular in recent decades because it is highly stable and does not quickly oxidize or corrode. Also, gold nanoparticles have a high extinction coefficient and efficient energy transfer properties, so they can enhance the detection signals, resulting in increased sensitivity and lower detection limits. Then gold nanoparticles are also biocompatible in the biomedical field. Several researchers successfully synthesize gold nanoparticles with different shapes for various applications using bottom-up methods, i.e., chemical reduction, electrochemical deposition, sol-gel and seed-mediated growth and top-down methods, i.e., mechanical milling, laser ablation, lithography, template-assisted synthesis, high-energy ball milling and plasma-based techniques. But, gold with a bipyramid shape is rarely reported, causing limited literature sources that discuss gold nanobipyramids (GNBPs). GNBPs have a stronger electric field enhancement than other shapes, so GNBPs are highly sensitive to surrounding medium change marked with the high value of Refractive Index Sensitivity (RIS) and Figure of Merit (FOM). Therefore, GNBPs have excellent potential to be implemented in various fields. This work discusses and overviews the synthesis method to produce GNBPs for further application. GNBPs can be fabricated through a synthesis process using microwave-assisted, one-pot, galvanic replacement and seed-mediated growth, with seed-mediated growth being the popular method. Then, GNBPs can be functionalized with several substances such as polymers, biomolecules, amine and thiol to bind with specific targeted analytes. Hence, due to their plasmonic properties, GNBPs are promising materials for many fields, especially sensing applications.

Simultaneous bright-field and fluorescence lensless imaging with high excitation light extinction for microfluidics applications

Lensless imaging fluorescence applications are limited by the unavoidable trade-off between the object-sensor distance and the excitation light attenuation at the detection plane. Indeed, a shorter object-sensor distance reduces the spreading of fluorescent signals but at the cost of losing excitation light attenuation provided by filter thickness. Accordingly, the combination of four synergistic pathways to attain further attenuation of excitation light is proposed: the optimization of total internal reflection by microfluidic chip geometry modification, cross-polarization extinction, interchangeable absorption longpass filters, and the CMOS sensor built-in bandpass Bayer filters. The advantages of such a combined setup are demonstrated with a microfluidic application, as we managed to keep the object-sensor distance as short as 600 µm and still distinguish the fluorescence of individual droplets, flowing as close as 650 µm to each other, while attenuating excitation light to an OD 5.9 level. This approach also allowed simultaneous fluorescence and bright-field observation of on-chip droplet fluorescence during flow at a rate of 30 fps. The enhanced capabilities in our scheme pave the way to further lensless fluorescence applications requiring parallelism, lower detection thresholds, and real-time acquisition, such as fluorescence biosensing.

A proteomics–bioinformatics approach to assess the molecular and physicochemical properties of brewer's spent grain protein concentrates: Effect of alkali-heat treatment

Brewer's spent grain (BSG) can serve as an attractive protein source due to its low cost and excellent nutritional and functional attributes. Alterations induced by protein extraction process in the BSG protein molecules can affect their functionality and nutritive value. This study investigated the effects of moderate heating during alkaline extraction on the molecular-physicochemical properties of BSG proteins. To this end, BSG protein concentrates were extracted at either room temperature or 50 °C, followed by proteomics and bioinformatics analyses. It was observed that the sample extracted at 50 °C contained proteins with a higher molecular weight, longer length, and enhanced stability relative to the sample extracted at room temperature. The content of acidic proteins showed a 14 % increase due to extraction at 50 °C. A simultaneous decrease in the content of both highly hydrophilic and highly hydrophobic proteins occurred in the sample extracted at 50 °C, while increasing the content of mildly hydrophilic proteins by approximately 25 %. This sample also contained a higher content of essential amino acids. Moreover, the content of proteins with a very high extinction coefficient (>50000 M−1cm−1) increased by 26 % due to extraction at 50 °C. Overall, these findings demonstrate that moderate heating during alkaline extraction can modulate the physicochemical and molecular properties of BSG proteins, providing insights into tailoring their functionality for specific industrial applications.

Traceable Measurement of High Polarization Extinction Ratio Based on Machine Vision

Traceable Measurement of High Polarization Extinction Ratio Based on Machine Vision

Tree traits are a stronger predictor of bee traits and species richness than taxonomic diversity

Abstract Functional traits help to understand biological diversity and the mechanism by which ecological communities are structured and how they respond to the environment. For example, the high tree species diversity within tropical forests can be grouped into a few functional attributes, wood density, size and dependence on animal pollination or seed dispersal. However, little is known about how these traits influence animal taxonomic and functional diversity in the forests. We carried out a vegetation census on six plots (20 × 100 m) within the National Forest of Carajás (Amazon biome) to identify forest canopy species and their functional traits. Within the same plot, we also applied three bee sampling methods (entomological nets, honey traps and scent traps). By characterizing the functional traits of trees and bees, we were able to predict bee functional diversity better than with taxonomic diversity alone via combinations of tree traits like size, wood density, dependence on pollinators and extinction risk. We found that larger trees with low wood density were negatively associated with small, eusocial tree cavity nesting bees. The richness and abundance of trees with high extinction risk was positively associated with the richness of medium‐sized solitary bees. The dominance in the community of pollinator‐dependent trees (average diameter in the basal area) was negatively associated with the richness of above‐ground and cavity nesting bees. Our findings suggest that the composition of the tree community limits the availability of nesting resources for specific groups of bees. Moreover, the presence of trees with higher extinction risk (conservation value) was associated with a greater variety of bee traits and was the only metric associated with overall bee richness. As expected, functional traits shed light on the mechanism that might drive high diversity within tropical forests. In addition, there appears to be complementarity in terms of conservation value and carbon stock potential, as areas that habour tree species with higher extinction risk and higher wood density are also those with overall greater bee and functional diversity. Finally, our study can contribute to the restoration of plant—pollinator community by providing an understanding of the vegetation community that contributes to biodiversity maintenance. Read the free Plain Language Summary for this article on the Journal blog.

High-Extinction Photonic Filters by Cascaded Mach–Zehnder Interferometer-Coupled Resonators

In this study, we demonstrate high-extinction stop-band photonic filters based on Mach–Zehnder interferometer (MZI)-coupled silicon nitride (Si3N4) resonators fabricated using I-line lithography technology. Leveraging the low-loss silicon nitride waveguide, our approach enables the creation of stable, high-performance filters suitable for applications in quantum and nonlinear photonics. With destructive interference at the feedback loop, photonic filters with an extinction ratio of 35 dB are demonstrated with four cascaded MZI-coupled resonators. This cascading design not only enhances the filter’s extinction but also improves its spectral sharpness, providing a more selective stop-band profile. Experimental results agree well with the theoretical results, showing linear scaling of extinction ratios with the number of cascaded MZI-coupled resonators. The scalability of this architecture opens the possibility for further integration and optimization in complex photonic circuits, where high extinction ratios and precise wavelength selectivity are critical for advanced signal processing and quantum information applications.

A Hemicyanine‐Based Highly Sensitive and Selective Near‐Infrared Fluorescent Probe for Fe3+ in Aqueous Media

ABSTRACTFerric ion is widely distributed in human cells and an important component of hemoglobin, which can promote the transportation of blood in the human body. Its ability to bind with oxygen is essential for participating in oxidation reactions and enzymatic reactions. Deficiency of iron (III) and excessive accumulation of iron in the blood can cause many health problems in the body, such as anemia, loss of appetite, fibrosis, reduced work routines, and decreased immunity. As a fluorescent dye, cyanine has the advantages of high fluorescence quantum yield, good optical and chemical stability, excitation and emission wavelengths in the near‐infrared region, high molar extinction coefficient, and small influence on pH variation. It is a fluorescent dye that modern scholars choose more. A new near‐IR hemicyanine derivative bearing 1,3‐dithiane moiety was developed as an efficient fluorescence probe 1 for the detection of Fe3+ in aqueous medium (THF/H2O, 1:1, v:v). This near‐IR fluorescence probe 1 exhibits high sensitivity and selectivity toward Fe3+ sensing with detection limit of 0.5 μM under lager scope of pH value (pH = 2–12).

JWST Observations of Young protoStars (JOYS)

Context. Due to the high visual extinction and lack of sensitive mid-infrared (MIR) telescopes, the origin and properties of outflows and jets from embedded Class 0 protostars are still poorly constrained. Aims. We aim to characterise the physical, kinematic, and dynamical properties of the HH 211 jet and outflow, one of the youngest protostellar flows. Methods. We used the James Webb Space Telescope (JWST) and its Mid-InfraRed Instrument (MIRI) in the 5–28 µm range to study the embedded HH 211 flow. We mapped a 0′.95 × 0′.22 region, covering the full extent of the blueshifted lobe, the central protostellar region, and a small portion of the redshifted lobe. We extracted spectra along the jet and outflow and constructed line and excitation maps of both atomic and molecular lines. Additional JWST NIRCam H2 narrow-band images (at 2.122 and 3.235 µm) provide a visualextinction map of the whole flow, and are used to deredden our data. Results. The jet-driving source is not detected even at the longest MIR wavelengths. The overall morphology of the flow consists of a highly collimated jet, which is mostly molecular (H2, HD) with an inner atomic ([Fe I], [Fe II], [S I], [Ni II]) structure. The jet shocks the ambient medium, producing several large bow shocks (BSs) that are rich in forbidden atomic ([Fe II], [S I], [Ni II], [Cl I], [Cl II], [Ar II], [Co II], [Ne II], [S III]) and molecular lines (H2, HD, CO, OH, H2O, CO2, HCO+), and is driving an H2 molecular outflow that is mostly traced by low- J, v = 0 transitions. Moreover, H2 0-0 S(1) uncollimated emission is also detected down to 2″-3″ (~650–1000 au) from the source, tracing a cold (T=200–400 K), less dense, and poorly collimated molecular wind. Two H2 components (warm, T =300–1000 K, and hot, T =1000–3500 K) are detected along the jet and outflow. The atomic jet ([Fe II] at 26 µm) is detected down to ~130 au from the source, whereas the lack of H2 emission (at 17 µm) close to the source is likely due to the large visual extinction (AV &gt; 80 mag). Dust-continuum emission is detected at the terminal BSs and in the blue- and redshifted jet, and is likely attributable to dust lifted from the disc. Conclusions. The jet shows an onion-like structure, with layers of different size, velocity, temperature, and chemical composition. Moreover, moving from the inner jet to the outer BSs, different physical, kinematic, and excitation conditions for both molecular and atomic gas are observed. The mass-flux rate and momentum of the jet, as well as the momentum flux of the warm H2 component, are up to one order of magnitude higher than those inferred from the atomic jet component. Our findings indicate that the warm H2 red component is the main driver of the outflow, that is to say it is the most significant dynamical component of the jet, in contrast to jets from more evolved YSOs, where the atomic component is dominant.

CLAMity: Mixtures of agricultural pesticides as multiple stressors in a bivalve species

Pesticides play a vital role in ensuring global food security amid a growing global population; however, their movement away from application sites can pose significant risks to the health of non-target species. Pollution of freshwater is a key contributor to the high extinction rates of freshwater species, which often face exposure to a complex “cocktail” of pollutants simultaneously. A better understanding of pesticide interactions will enable more targeted policies and land management practices to mitigate environmental damage while ensuring food security. In this study, Corbicula fluminea (Asian clam) were exposed to binary pesticide mixtures commonly found in two rivers in the South of England. The exposures involved individual pesticides and mixtures at a concentration of 0.1μg/L per pesticide. Selected molecular markers were targeted and proved to be impacted by the timing and the pesticide mixture; an Integrated Biomarker Response (V2) value was also calculated. Our results show that both seasonality and the chemicals characteristics of the pesticides may significantly modulate their toxicity, both individually and in a mixture. When put into the context of catchment management this data combined with pesticide monitoring could improve estimating ecological risk. To the authors’ knowledge, this is the first study to assess the molecular responses of these mixtures in bivalve molluscs using the IBRv2 value following exposure to combined pesticides.

Broadband metamaterial polarizers with high extinction ratio for high-precision terahertz spectroscopic polarimetry

The demand for precise polarizers is increasing to investigate the polarization characteristics of materials non-invasively in the terahertz region. Recently, to address the low extinction ratio and fragile nature of conventional wire-grid polarizers, plasmonic structures and metasurfaces have been proposed. However, the challenge of achieving low transmittance compared to a high extinction ratio, along with the bulky structure due to a thick substrate, remains to be addressed. Here, we present high-efficiency broadband metamaterial polarizers consisting of cross-aligned double-layers of subwavelength metallic slit arrays, leveraging the extraordinary optical transmission and funneling effects. We obtained extinction ratios exceeding 70 dB over a broad frequency range, from 0.2 to 2.5 THz, reaching a maximum extinction ratio of ∼90 dB at 0.7 THz. To investigate the influence of high extinction ratio polarizers on actual measurement results, we measured a non-Hermitian metasurface with asymmetric polarization conversion and analyzed them using the Jones matrix formalism. The results confirmed that the extinction ratio of the polarizer has a significant impact on precise polarization-dependent measurements, especially on cross-polarization measurements. The enhanced performance of our polarizers offers significant potential for sensitive THz systems, paving the way for advancements in polarization analysis of emerging materials and chiral sensing.

Synthesis and characterization of new organometallic lanthanides metal complexes for photodynamic therapy

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{10}^{6}$$\\end{document} M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable.

First map of D2H+ emission revealing the true centre of a prestellar core: Further insights into deuterium chemistry

Context. IRAS 16293E is a rare case of a prestellar core being subjected to the effects of at least one outflow. Aims. We want to disentangle the actual structure of the core from the outflow impact and evaluate the evolutionary stage of the core. Methods. Prestellar cores being cold and depleted, the best tracers of their central regions are the two isotopologues of the trihydrogen cation that are observable from the ground: ortho-H2D+ and para-D2H+. We used the Atacama Pathfinder EXperiment (APEX) telescope to map the para-D2H+ emission in IRAS 16293E and collected James Clerk Maxwell Telescope (JCMT) archival data of ortho-H2D+. We compared their emission to that of other tracers, including dust emission, and analysed their abundance with the help of a 1D radiative transfer tool. The ratio of the abundances of ortho-H2D+ to para-D2H+ can be used to estimate the stage of the chemical evolution of the core. Results. We have obtained the first complete map of para-D2H+ emission in a prestellar core. We compare it to a map of ortho-H2D+ and show their partial anti-correlation. This reveals a strongly evolved core with a para-D2H+/ortho-H2D+ abundance ratio towards the centre for which we obtain a conservative lower limit from 3.9 (at 12 K) to 8.3 (at 8 K), while the high extinction of the core is indicative of a central temperature below 10 K. This ratio is higher than predicted by the known chemical models found in the literature. Para-D2H+ (and indirectly ortho-H2D+) is the only species that reveals the true centre of this core, while the emission of other molecular tracers and dust are biased by the temperature structure that results from the impact of the outflow. Conclusions. This study is an invitation to reconsider the analysis of previous observations of this source and possibly questions the validity of the deuteration chemical models or of the reaction and inelastic collisional rate coefficients of the H+3 isotopologue family. This could impact the deuteration clock predictions for all sources.

Diffuse interstellar bands as dust indicators: The contribution from 3D maps

Context. Three-dimensional (3D) distributions of the 862 nm diffuse interstellar band (DIB) carrier have been computed based on Gaia parallaxes and DIB catalogues, in parallel with 3D maps of dust extinction density. Three-dimensional maps provide local diagnostics and information on the distribution of structures in addition to line-of-sight (LOS) integrated quantities, and allow us to focus on poorly studied low-extinction areas. They make cross-matching with other catalogues possible through estimates of the DIB and extinction along any given path. Aims. We re-examined the relationships between the density of DIB carriers and the absorption and emission properties of spatially co-located dust. Along with laboratory identifications of carriers, these properties may shed light on the formation and evolution of this organic matter. They may also help to model dust emission and absorption properties in a more detailed way. Methods. We used the 3D maps of 862 nm DIBs and of dust extinction, as well as available DIB equivalent width (EW) catalogues and published measurements of parameters characterizing the dust extinction law and the dust emission. We studied the relationships between the extinction-normalized 862 nm DIB EW and the extinction level, the total-to-selective extinction ratio RV, and the dust far-IR emission spectral index β. We re-visited the link between several DIBs and the UV absorption bump at 220 nm. Results. The ratio of the 862 nm DIB carrier density to the optical extinction density (DIBnorm862) is increasing in low-density clouds, confirming with local values the trend seen in the LOS data. In both cases, the coefficients of a fitted power law fall within the range of those measured towards SDSS high-latitude targets for 20 different bands, ranking this DIB among those with a high increase, above that of the broad 4430 Å DIB. This is consistent with the recent measurement of a larger scale height above the Plane for the 862 nm DIB compared to that of the 4430 Å DIB. Using map-integrated 862 nm DIB EWs and extinctions along the paths to APOGEE targets with published proxies R′V for the total-to-selective extinction ratio, we found that, despite a large scatter, DIBnorm862 is positively correlated with R′V for those stars with low to moderate extinctions (AV = 0.2 to 2–3 mag). Independently, using stars from the 862 nm DIB catalogue located outside the disk and for the same regime of extinction, DIBnorm862 is found to be globally anti-correlated with the Planck opacity spectral index β. This is consistent with the observed anti-correlation between β and R′V. In the light of a recent result on the variability of the carbon/silicate ratio in dust grains as a source of this anti-correlation, it suggests that DIBnorm862 increases with the fraction of carbonaceous to silicate grains in the co-located dust, in agreement with the carbonaceous nature of DIB carriers and recent evidences for a spatial correlation between DIBnorm862 and the fluxes of carbon-rich ejecta of asymptotic giant branch (AGB) stars. At higher extinction both trends disappear, and there is evidence for a trend reversal. Regarding the link between the height of the 220 nm UV absorption bump and extinction-normalized EWs of DIBs, we found that two factors explain the absence of previous clear results: the correlation disappears when we move from σ-type to ζ-type DIBs and/or from single-cloud LOSs to paths crossing multiple clouds distant from each other; ζ-type bands can be used to predict low and high values of the bump height, provided one adds a correcting factor linked to the ambient radiation field (e.g. the 5780/5797 DIB ratio). We show examples of simple models of the bump height based on the 5780 Å band, the 5850 Å band and the 5780/5797 DIB ratio. We also found an anti-correlation between DIBnorm and the width of the bump, which similarly disappears from σ-type to ζ-type DIBs. This suggests that a fraction of the bump is generated outside the dense molecular clouds. Conclusions. There are complex relationships between DIBs and dust; however, massive measurements of DIBs and extinction and the derived 3D maps may provide some constraints on the density, the nature, and the contribution to extinction and emission of the co-located dust. This requires large stellar spectroscopic surveys and space-based measurements of UV extinction.

JWST View of Four Infant Galaxies at z = 8.31–8.49 in the MACS J0416.1−2403 Field and Implications for Reionization

New JWST/NIRCam wide-field slitless spectroscopy provides redshifts for four z > 8 galaxies located behind the lensing cluster MACS J0416.1−2403. Two of them, “Y1” and “JD,” have previously reported spectroscopic redshifts based on Atacama Large Millimeter/submillimeter Array measurements of [O iii] 88 μm and/or [C ii] 157.7 μm lines. Y1 is a merging system of three components, and the existing redshift z = 8.31 is confirmed. However, JD is at z = 8.34 instead of the previously claimed z = 9.28. JD’s close companion, “JD-N,” which was a previously discovered z > 8 candidate, is now identified at the same redshift as JD. JD and JD-N form an interacting pair. A new candidate at z > 8, “f090d_018,” is also confirmed and is at z = 8.49. These four objects are likely part of an overdensity that signposts a large structure extending ∼165 kpc in projected distance and ∼48.7 Mpc in radial distance. They are magnified by less than 1 mag and have an intrinsic M UV ranging from −19.57 to −20.83 mag. Their spectral energy distributions show that the galaxies are all very young with ages ∼ 4–18 Myr and stellar masses of about 107–8 M ⊙. These infant galaxies have very different star formation rates ranging from a few to over a hundred solar masses per year, but only two of them (JD and f090d_018) have blue rest-frame UV slopes β < −2.0 indicative of a high Lyman-continuum photon escape fraction that could contribute significantly to the cosmic hydrogen-reionizing background. Interestingly, these two galaxies are the least massive and least active ones among the four. The other two systems have much flatter UV slopes largely because of their high dust extinction (A V = 0.9–1.0 mag). Their much lower indicated escape fractions show that even very young, actively star-forming galaxies can have a negligible contribution to reionization when they quickly form dust throughout their bodies.

Molecular Engineering of membrane structure targeted photosensitizers for antitumor photodynamic therapy

Photodynamic therapy (PDT) has been used to cure special diseases or the diseases that localized at special sites in comparison with conventional therapy, due to its high spatiotemporal selectivity, non-invasion, low drug resistance. However, vast majority of photosensitizers (PSs) still suffer from several limitations including poor aqueous solubility and poor photostability. Here, we used two strategies, promoting the intramolecular charge transfer and terminal modification, to overcome these limitations and enhance therapeutic effects. Three membrane-structure targeted molecules, 3CN-Np, 3CN–OH, and 3CN-QA, were designed and synthesized, which exhibited high extinction coefficient, excellent photostability and reactive oxygen species (ROS) productive capacity. In cell imaging, the designing molecules would stain endoplasmic reticulum for 3CN-Np and 3CN–OH, and cell membrane for 3CN-QA, respectively. Afterwards, we used white light (25 mW/cm2) to irradiate the probe cultured cells for 20 min, the ratio of the dead and live cells was 3.0 for 3CN-Np, 3.5 for 3CN–OH, and 3.7 for 3CN-QA. Based on the high cell apoptosis in vitro under a white-light, 3CN–OH was selected to inhibited tumor growth in vivo, and the tumor volume was reduced to 45 % with non-toxicity to vitals. The study provided new sights in developing PSs with high water-solubility, photostability, and ROS generating ability in white-light mediating PDT system.

Theoretical Analysis on Active Polarization Control of Fiber Laser Based on Root Mean Square Propagation Algorithm

High-power linearly polarized fiber lasers are widely used in coherent beam combination, nonlinear frequency conversion, and gravitational wave detection. With the increase in output power, it is challenging for fiber lasers to maintain a high polarization extinction ratio (PER). Combined with intelligent techniques, active polarization control is a prospective method to obtain the laser output with high PER and high stability. We demonstrate a comprehensive model of an active polarization control system. The root mean square propagation (RMS-Prop) algorithm is used to control the non-polarization-maintaining (non-PM) fiber laser to generate linearly polarized laser. The parameters of the RMS-Prop algorithm are theoretically analyzed, including cost function, perturbation amplitude, and global learning rate. The simulation results show that PER is the optimal cost function. When the perturbation amplitude is 0.06 and the global learning rate is 0.6, the system can achieve the optimal control speed and accuracy. By comparison with the stochastic parallel gradient descent (SPGD) algorithm, the RMS-Prop algorithm has an advantage in obtaining higher PER.